Demonstrates how to set public field objects : Class « Reflection « Java Tutorial

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/*
 *     file: HiddenFieldModification.java
 *  package: oreilly.hcj.reflection
 *
 * This software is granted under the terms of the Common Public License,
 * CPL, which may be found at the following URL:
 * http://www-124.ibm.com/developerworks/oss/CPLv1.0.htm
 *
 * Copyright(c) 2003-2005 by the authors indicated in the @author tags.
 * All Rights are Reserved by the various authors.
 *
 ########## DO NOT EDIT ABOVE THIS LINE ########## */

import java.lang.reflect.Field;

/**
 * Demonstrates how to set public field objects.
 * 
 * @author <a href=mailto:kraythe@arcor.de>Robert Simmons jr. (kraythe)</a>
 * @version $Revision: 1.3 $
 */
public class HiddenFieldModification {
  /**
   * Sets all int fields in an object to 0.
   * 
   * @param obj
   *          The object to operate on.
   * 
   * @throws RuntimeException
   *           If there is a reflection problem.
   */
  public static void initIntFields(final Object obj) {
    try {
      Field[] fields = obj.getClass().getDeclaredFields();
      for (int idx = 0; idx < fields.length; idx++) {
        if (fields[idx].getType() == int.class) {
          fields[idx].setAccessible(true);
          fields[idx].setInt(obj, 0);
        }
      }
    } catch (final IllegalAccessException ex) {
      throw new RuntimeException(ex);
    }
  }

  /**
   * Demo Method.
   * 
   * @param args
   *          Command line arguments.
   */
  public static final void main(final String[] args) {
    Integer value = new Integer("123");
    System.out.println("Before: " + value);
    initIntFields(value);
    System.out.println("After: " + value);
  }
}

/* ########## End of File ########## */